1. d4 c5?


1d4,c5 is the Old Benoni.
a) it is a good opening. as stated above, white can take with 2.dxc5 but white generally cannot hold the pawn and there is a serious opening trap if white misplays.
his other options are:
b) pushing to d5. probably the best response and if black plays properly he can reserve the options of playing any of the other Benoni games.
c) protect the pawn with e3, c3, Nf3, or even Be3.